This SBIR Phase I/Phase II Fast-Track proposal is intended to develop a novel therapy for patients with sepsis and septic shock. Septic shock is the leading cause of death in non-cardiac intensive care units. Despite advances in the management of trauma victims, the incidence of sepsis and septic shock has increased significantly. More than 750,000 patients develop sepsis and septic shock each year with an overall mortality rate of 28.6% in the US alone. The global market potential for sepsis treatment is estimated at over $30 billion annually. Thus, successful development of a novel and effective anti-sepsis therapy will not only have a positive impact on health care, but will also have significant commercial benefits. Although apoptosis plays an important role in the pathobiology of sepsis, the clearance of apoptotic cells has largely been ignored. Recent evidence shows that the opsonizing protein milk fat globule epidermal growth factor-factor VIII (MFG-E8) is involved in apoptotic cell clearance. We have discovered that downregulation of MFG-E8 is responsible for the reduced apoptotic cell clearance in sepsis. Early administration of rat MFG-E8-containing exosomes or recombinant murine MFG-E8 (rmMFG- E8) increases phagocytosis of apoptotic cells, reduces proinflammatory cytokines, and improves survival in a rodent model of septic shock. However, one obstacle hampering the development of MFG-E8 as a therapeutic agent for septic patients is the potential immunogenicity of animal proteins in humans. To overcome this, we have successfully expressed recombinant human MFG-E8 (rhMFG-E8). Our data strongly suggest that rhMFG-E8 is as effective as animal MFG-E8. We therefore hypothesize that administration of rhMFG-E8, even late after the onset of sepsis, improves cardiovascular function, attenuates tissue injury and inflammation, and reduces mortality. The primary goal of this SBIR Fast-Track project is targeted toward completing the preclinical development of rhMFG-E8 as a novel therapeutic agent in reducing mortality in septic shock. In the Phase I Segment, we will 1) scale up the production of rhMFG- E8;and 2) further confirm the beneficial effect of rhMFG-E8 in a rodent model of septic shock. These readily achievable milestones should provide useful feasibility information that will allow us to conduct the proposed Phase II experiments. In the Phase II Segment, we will 3) determine the dose-response effect and time-course (delayed administration) of rhMFG-E8 on apoptosis, cardiovascular responses, tissue injury, inflammation, and survival in a rodent model of septic shock;4) assess the toxicity and pharmacokinetic properties of rhMFG-E8 in normal and septic animals;and 5) determine the efficacy of rhMFG-E8 in a swine model of septic shock. These proposed studies should provide useful preclinical information that will allow us to file an IND application to the FDA for initiating clinical trials in order to obtain commercial utilization of rhMFG-E8 as a safe and effective therapy for patients with sepsis and septic shock.